lemelson



May 5, 1964 J, H. LEMELSON EXTRUSION APPARATUS 5 Sheets-Sheet 1 OriginalFiled 001:. 22, 1957 May 1964 J. H. LEMELSON EXTRUSION APPARATUS 3Sheets-Sheet 2 Original Filed Oct. 22, 1957 WNW L Q A S E WIIIIIIII May5, 1964 H. LEMELSON EXTRUSION APPARATUS 3 Sheets-Sheet 5 Original FiledOct. 22, 1957 United States Patent 25,570 EX'IRUSION APPARATUS Jerome H.Lemelson, 8B Garfield Apartments, Metuchen, NJ.

Original No. 3,002,615, dated Oct. 3, 1961, Ser. No. 691,622, Oct. 22,1957. Application for reissue Oct. 2, 1962, Ser. No. 228,223

18 Claims. (Cl. 18-12) Matter enclosed in heavy brackets [II appears inthe original patent but forms no part of this reissue specification;matter printed in italics indicates the additions made by reissue.

This invention relates to extrusion apparatus and in particular toautomatic extrusion machinery for producing elongated extrusions whichvary in cross section with length.

In general this invention relates to apparatus for extruding metal orplastics by a process which will hereafter be referred to asstop-extrusion which process involves machinery for effecting motion ofone or more blades or stop extrusion tools over an extrusion dieopening, or in and out of said die opening in a manner to change thecross-sectional shape of a member formed therein without the necessityof machining said member to effect said changes in shape. By controllingthe mo tion of the stop-extrusion tool in degree as Well assynchronizing its motion to occur at a predetermined time during anextrusion cycle, an elongated member such as a tube, beam, plate, rod orother structural shape may be provided having one or more integrallyformed projections extending from said member at predetermined pointsalong its length. Slots in its wall or changes in internal cross-sectionmay also be provided at predetermined lengths of said extrusion whichshape variations may eliminate one or more postforming or machiningoperations. A programmed automatic control system is provided forrapidly altering the sequencing as Well as the degree of operation ofthe stop-extrusion means so that a product may be produced conforming toa particular order. As a result the set-up or sequential control meansmay be easily varied with minimum downtime required to produce anotherproduct thereafter conforming to other requirements.

Accordingly, it is a primary object of this invention to provide new andimproved machinery for forming materials such as metals and plastics ina manner whereby one or more postforming operations are eliminated.

Another important object is to provide new and improved extrusionmachinery for extruding material to shape which varies in cross-sectionwith length.

Another object of this invention is to provide new and improvedextrusion apparatus having means for automatically varying the shape ofmaterial expressing therefrom as it is formed and including automaticpro gramming and control means for predetermining the points along saidextrusion where said changes may occur as well as controlling the degreeof said changes.

Another object is to provide improved means for controlling theextrusion rate as well as the operation of various tools for changingthe shape or cross-section of an extrusion as it extrudes from a die.

Another object is to provide new and improved means for extruding tubingand other walled shapes with open- Re. 25,570 Reissued May 5, 1964 ingsin the Walls thereof of predetermined shape and length at predeterminedsections of said tubing.

Another object is to provide an improved means for extruding andsimultaneously Working on such materials as thermoplastic plastics andmetals.

With the above and such other objects in view as may hereafter morefully appear, the invention consists of the novel constructions,combinations and arrangements of parts as will be more fully describedand illustrated in the accompanying drawings, but it is to be understoodthat changes, variations and modifications may be resorted to which fallwithin the scope of the invention, as claimed.

FIG. 1 is a partly sectioned, partial side view of an extruding machinemade in accordance with the teachings of this invention and alsoillustrating an extruded shape and means tor forming said shape.

FIG. 2 is a fragmentary cross-section of a tubing extnusion press havingmeans for varying the external shape of said tubing, with thecross-section being taken through line 22 of FIG. 3 looking in thedirection of arrows 22;

FIG. 3 is an end view of FIG. 2 with parts broken away for clarity;

FIG. 4 is a partial view of the apparatus of FIG. 2 modified with meansfor supporting the means tor varying the external shape of the tubing;

FIG. 5 is a schematic and block diagram of an automatic control systemand apparatus of this invention controlled thereby, and

FIG. 6 shows a modified control diagram for apparatus of this inventionemploying a hydraulically operated servo and is applicable to FIG. 5.

FIG. 6a shows a modified form of control applicable to replace certaincomponents in FIG. 6 and FIG. 6b shows details of automatic controlmeans applicable to the apparatus of FIG. 5.

FIG. 1 shows in partial cross-section details of an extrusion apparatusincluding an extrusion press 10 having a die section comprising a diechamber member 11 with a die 12 secured at one end of the chamber 14 andheld by an end plate 13. The expressing of 'flowable material such asaluminum or plastic through the extruder is effected at room temperatureby conventional pressure expressing means. In the apparatus of FIG. 1, apiston 20 travels longitudinally in the chamber '14 by the action of oneor more hydraulic cylinders 27 one of which is shown with its ram 2'6connected to the rear section 22 of piston 20 through two or more rods25 and a yoke plate 24. The rods 25 travel axially in bearings in a baseplate 19 secured to the frame 21 of the press. Said frame 21 alsosupports the piston prime moving cylinder 27. A mandrel 16 for formingthe inside wall of the tubing is axially movable in a base 20a in thehead end of the piston and is urged in reciprocating motion therein, sothat its far end travels in and out of the bore of die block 12, by theram 18' of a second hydraulic cylinder 18 secured to the bearing plate19. Thus, as the piston 20 torces material out the opening in die 12 bymovement towards said die, the smaller piston or mandrel 16 may beoscillated in the opening in said die at predetermined points in theextrusion cycle, a predetermined de-' gree in a range of longitudinalpositions from one in which only a solid rod section having the diameterof the die hole will be extruded, to a position whereby a tube is shapedhaving a wall with an inside diameter equal to the outside diameter ofthe mandrel in the opening in the die. Depending on the shape of the endof the mandrel over which the expressed material flows and the degreeand manner in whch said mandrel is manipulated, tubing having a wallshape which varies in crosssection with length in a predetermined mannermay be derived by automatic control of the mandrels 1ongitudinal motionand by controlling the speed of the ram of the hydraulic cylinder 13 byvarying the pressure at the inlet and exhaust lines 17 and 17 to thecylinder of 1 8. The operation may be effected automatically andvariations in the position of the tools and speed of operation of theservo which effects extrusion rate may be controlled to occur atpredetermined times during the extrusion cycle to provide a tube or anyelongated structural shape of predetermined cross-section change.

As an example, the cylindrical extruding member 15 is shown with one ormore solid sections 42. provided at predetermined positions along thelengths of the tubular member. Manipulation of the mandrel 16 so that itprojects far enough into the opening of the die 12 through which thematerial is expressing, will provide a shape which is equivalent incross-section to the annular volume defined by the diametrical surfaceof mandrel 16a and the wall of the die opening. As the mandrel nose 16ais retracted by the action of cylinder 18 and moves backward into thechamber 14, since the nose lea tapers or reduces in cross-section, theannular extrusion area through which material is permitted to extrudewill increase and eventually a solid cross-section such as 42 will beformed in the extrusion which may extend for a predetermined length ofthe member 15 depending on the time the mandrel remains retracted duringthe extrusion process. Depending on the shape of the mandrel nose 16aand the degree said mandrel is moved in and out of the die opening, avariety of different internal cross-sections may be provided includingsections having internal shelves, flanges, or plug-like formations suchas 42 with or without enclosed or restricted openings such as 41extending longitudinally therethrough. Automatic control of the degreeof motion or position of the ram of cylinder 18 as well as the timing ofsuch action may be effected by means of an automatic controller whichmay also be adapted to control the operation of cylinder 27 and thespeed and degree of travel of piston 20. Other apparatus may also becontrolled by the same controller for further finishing the extrusionand effecting a mark thereon or cutting off or otherwise shaping saidextrusion. If the control means is properly timed and sequenced relativeto the start of the'extrusion cycle, a structural member or tube may beproduced having internal changes in cross-section, such as the solidplug-like closure sections 42 at predetermined points in its length. Ifthe locations of sections 42 of the member 15 are maintained and known,and it is later desired to perform further shaping operations at saidsections, or to effect bends on the thinner wall sections 40therebetween, said operations may be performed in another machine whichis set up and sequenced to perform said operations using an end of asection of the member 15 as a reference point or bench mark. Thisassumes that the cutolf point of the extrusion 15 or the position atwhich a predetermined point in the extrusion begins or ends is known.

FIG. 1 also illustrates other apparatus which may be employed forfurther finishing operations on the member 15 as it is extruded. Thenotation 39 refers to a solenoid or fluid cylinder operated marking toolwhich may be controlled by said sequential or a feedback control meanscontrolling the extrusion and mandrel operating cylinders to effect amark or small indentation in the outer surface of the member 15 at eachof the solid cross-section sections 42 to indicate their positions forindicating where to perform operations such as drilling, bending,cutting, etc. The notation 5G refers to a roller conveyor or the likefor supporting the member 15 as it extrudes and preventing itsdeformation due to the forces applied by tool 39. The tool 39 may alsobe a drill or punching tool for partly or completely penetrating andproviding a hole or cavity in the sections 42 or the thin walledsections 40 between said solid plug sections. While 39 is shown securedto part of the frame or mount 21 for the press, it may also be mountedon a carriage such as 47 which is movable when actuated in the directionof extrusion and is adapted to move at the same rate as the member 15 toserve as a so-called flying mount for the tool 39 so that said tool mayperform an operation on 15 while fixed relative to said extrudingmember.

The notation 32 refers to a hydraulic cylinder mounted on the end of thedie chamber 11 which is adapted to project a blade or tool 30 against 15to reduce the crosssection thereof. The tool or blade 31 may alsopertain to a shear for cutting of the member 15, into predeterminedlengths and is preferably under the control of the means forautomatically controlling the other servos. The numerals 28 and 29 referto a pair of rollers, one of which is power operated, which may beutilized for further guiding and driving the member 15 away from thechamber 11 after cutolf.

Cutoff may also be effected by stepping the mandrel in shape as at 16c.When 16c is moved into the con stant diameter section of the die opening12 it acts as the plunger of a valve and is shaped to reduce the annularextrusion area when projected to or near zero clearance so that saidextrusion is stopped or the wall 41) is made so thin that simple meansmay be employed to part the member 15.

In order to effect the formation of the solid plug sec tion 42 withoutreducing the speed at which the member 15 is extruding, it will benecessary to increase the rate of travel of the piston 20 so that theextrusion material rate of flow will increase during the period it isshaped into section 42. An increase in the rate of travel of said pistonmay also be required, depending on the characteristics of the materialbeing extruded, to prevent buckling of the thin wall 40 as 16 iswithdrawn. The changes in speed of travel of piston 20 may be effectedautomatically by means of a predetermining controller which alsocontrols all the servos employed.

If a plastic or material other than metal is utilized as the expressingmaterial, the conventional screw conveyor extrusion means may beemployed in place of the piston 20 and the rate of flow of theexpressing material may be controlled by controlling the rate ofrotation of the screw.

FIGS. 2 and 3 show the extrusion apparatus of FIG. 1 modified with meansfor varying the external shape of tubing or structural member extrudedtherefrom. The apparatus will produce tubing having one or more shelvesor flanges of predetermined length projecting at predetermined sectionsalong said extrusion which may be used for strengthening or stiffeningsaid tubing, to effect improved and simplified fastening of saidextrusion to other members and for other functions.

In FIGS. 2 and 3 the die 12' is shown as having a through and throughhole of irregular shape comprising a section 12a which is circular incross-section and a radially extending opening portion 12b in the shapeof a slot for the formation of an elongated extrusion with a ridge orshelf 34 projecting from the section extruded through 12a. A stop-gate30 is mounted adjacent the end of die 12 which comprises a tool 39 ofhardened metal with a bevelled nose 30a adapted to slidably engage theface 11a of the die block and to be urged by a ram 31 of a hydrauliccylinder 32 to cover and uncover the end of the projecting section 12bof the hole in the die 12. Thus, if tool 30' is moved radially acrossand away from opening 12b as material is extruded through said die, oneor more of the formations 34 may be provided projecting from the surfaceof the extrusion 15. The length and position of a formation 34 will be afunction of the time during which extrusion tool 30' is positioned overthe section 12b of the die hole and the amount of time it remainscovering said section. The numeral 33 refers to a support for the tool30 between which and the face 11a of the die block, said tool isslidably engaged. Support 33 is preferably bolted to the die block 11 asis the cylinder 32. A lineal ball bearing 35 may be secured to the block33 to bear against the tool blade 30 to reduce friction and facilitatemovement of the tool across and radially away from the opening 12b.

FIG. 4 shows apparatus for urging one or more stop extrusion blades 30'in forced engagement against the face of the die or extruder housing inwhich said blade is supported against deflection. The mechanism of FIG.4 may be used where the material being extruded has a tendency to flowbetween the face of the die, or extruder, and the blade, when the latteris advanced over all or part of the opening, thus resulting in anundesirable material leak which may atfect the shape of the extrusion.In FIG. 4, the blade 30' is first driven against the extruding materialstopping oif part of the flow, as shown, to change the shape of theextrusion. A cam 48 mounted on a shaft 49 is then rotated by the actionof a servo (not shown) which causes a surface 48' of the cam to engagethe outer surface of the blade 30 and urge or force said blade againstthe face 11' of the .die or extruder front wall, thereby effecting aseal between said blade and ill. When 48 is again rotated clockwise, itdisengages 30 allowing the latter to be withdrawn from the .die opening.The operation of the servo advancing and retracting the blade may beinterlocked with and synchronized to occur prior to and after therespective locking and unlocking actions of the cam 48. The shaft 49 ofcom 48 is preferably supported by bearings secured to the extruder 11 orthe frame 21 therefor so that its position remains fixed relative to theface of 11.

FIG. 5 illustrates programming and automatic control means forcontrolling the extrusion apparatus of FIGS. 1 to 4 or the like. In thediagram, as well as in the others employing electrical control means, itis assumed that, where not illustrated, the proper power supplies areprovided on the correct sides of all switches, controls, amplifiers,etc. Where illustrated, the notation P.S. refers to a power supply.

As requirement for the length and position of crosssectional changes inthe extrusion such as the internal plug-like sections 42 and/or thelocation and length of externally extending lugs such as 34, or cutouts,slots or indentations formed by stop tools such as 30 of FIGS. 1 and 4,may vary iirom one production run or order to the next, it is desirablethat means he provided for rapidly and easily changing the sequentialcontrol means -for controlling the degree and direction of movement ofthe various tools such as mandrel 16 as well as the speed and directionof motion of the extrusion piston v20. Other servo means which may bedesirably synchronized or interlocked to the movement of the mandrel 16and piston 20 include the servo means for advancing and retracting thestop tool 30, which servo may also be controlled in speed and position,the servo means for operating the cut-ofi tool for severingpredetermined lengths of the extrusion from the material expressing fromthe die, the servo means for operating the marking tool 39 forindicating the positionsof variations in internal shape by providingmarks on the outside of the tube. It may also be required to control thespeed of the powcred rollers used for drawing or conveying the extrusionaway from the extruder before and/or after severance of a length thereoffrom the expressing material. The sequential control may also beprovided for such auxiliary apparatus as a valve or valves for effectingthe flow of a fluid through :the mandrel to provide a fluid in thechamber or chambers 41 for encapsulation of said fluid therein, and orother auxiliary machining equipment such as described operations on theextruding or extruded sections.

In FIG. 5, automatic sequential control of the various servo componentsof an automatic extrusion system utilizing one or more of the describeddevices for varying or operating on a section of material as itexpresses from an extrusion machine, is effected by reproducing andutilizing signals recorded in a predetermined order on the surface of amagnetic drum or tape 200 moving at constant velocity or intermittentlymoved past multiple reproduction transducer heads T to T7. A constantspeed controlled motor 201 drives the shaft 202 of a pulley or drum 20'1driving a closed loop magnetic tape 200-, which tape has command signalsrecorded on respective tracks thereof to effect a predetermined sequenceof actions. While the complete tape transport is not shown, means arepreferably provided for rapidly changing the closed loop tape 30 orerasing the signals recorded thereon and recording new signal-s so thatthe sequence and type of operations performed on predetermined lengthsof the member 15 extruded from the extrusion press '11 may be rapidlyaltered with negligible downtime required to effect said change.

In FIG. 5 oontnol of the lineal servo devices 18 and 27 whichrespectively control the degree of movement and speed of the mandrel 16and the extrusion piston 20, is eifected by means of anelectro-hydraulic pump servo system. Illustrated, although notnecessarily limited thereto, a two-way variable displacement hydraulicpump used in a closed loop system with an electro h ydnaulic strokerwhich varies pump delivery rate in proportion to a low level electricalinput signal. Such a pump and control system therefore, is described in:the April 1957 issue of Control Engineering Magazine.

Two means for effecting automatic control using electro-hydraulic pumpservos are provided. Lln FIG. 5, one or more analog signals of varyingamplitude are recorded on respective channels of the magnetic tape 200and are each reproducible to provide a time variable voltage which isused to control an electric stroker 204 which in turn controls theposition of a slide block of a variable displacement hydraulic pump 206through a hydraulic stroker 205. The block notation 203 refers to thecombination of the electric stroker 204, input thereto, hydraulicstroker 20-5, and hydraulic pump 206 and the other reference notationsfor blocks 203a, 203b, etc, are assumed to contain components similar tothose provided in 203 for controlling other servos or hydrauliccylinders as described. The characteristics of the variable displacementhydraulic pump 206 are such that, depending on the position of the slideblock thereof, which is controlled by the electro-hydraulic stroker, itmay pump in eitherdirecti-on and hence the position as well as thedirection of motion of the ram of the hydraulic cylinder controlledthereby will be a function of the amplitude of the analog signalreconded on the channel of 200 controlling said servo or the voltageinput to the eleotnic stroker.

The feedback loop of the system 203, which controls the position anddirection of motion of the ram 26 of cylinder 27 and hence the motion ofthe extrusion piston 20, includes a potentiometer 208 having a wiper armwhich is coupled, via gears or the like, to the movement of ram 26.Hence, the value of the resistance of 208 is a function of the positionof 26 and the piston 20. The command signal voltage is reproduced bypicle up transducer T reproducing the analog signal from 200, which isamplified by linear amplifier A and is ed as a proportional voltagesignal to the input 203" -f controller 203. The notation 203 mayrepresent a .evice such as a voltage comparator of known design, whichis adapted to provide an error signal or a sumaing amplifier, the inputsof which are connected to eceive the variable voltage signals from 208and A he output of the summing amplifier 203" is used to on'trol theelectric stroker 204. Said output or error ignal voltage drives themotor of the electric strolier 04 until the output of the feed-b ackpotentiometer 20 8 quals the voltage output of A The electric stroterrotor in turn controls a valve plunger through precision caring andhence effects control of the hydraulic stroker 05. Thus, depending onthe characteristics or rate of hange of amplitude of the signal recordedon the chanel of 200 from which T is reproducing, the piston 20 may notonly be controlled in position but its speed 11d rate of changeof speedmay be controlled and according to the described requirements forinreasing'or decreasing the flow of material through the ie as themandrel 16 is moved relative thereto and ates different flowsthere-Ahrough to change the internal toss-section of the extrusion. In asimilar manner, the ydrau lic cylinders '13 and 32 controlling themandrel iston 16 and stop blade 30 may be controlled by means f thecontrol systems 203a and 293b, each of which eceives a variable voltageinput over the circuits Zild-a' nd 203b' which connects to respectiveamplifiers in the utputs of respective reproduction transducers which:produce respective control signals from respective chanels of tape 200.If multiple stop-extrusion blades are rovided in a side by side array,for controlling width r formations on a wide extrusion, then each may beontrolled by separate units 203a if positional control f said blades isdesired, or merely by valving fluid to ither side of the pistoncontrolling the blade if the only ontrol required as to advance theblade and retract it t predetermined positions in the cycle. Suchcontrol may be efiected by the use of monostable solenoid valves )r gatin-g fluid under pressure from a reservoir to pump either side of thepiston of the cylinder 32 for con- 'olling the projection or retractionof said blade. The )lenoid valve or valves, which may occupy thepositions 203a or 203b of FIG. 5, may be controlled to switch "om aposition whereby the stop tool is retracted to an dvanced or projectingposition such that the shape of 1c extruding member is changed when asignal of the :quired amplitude is reproduced from the respective ack of200 and this signal is used as an actuating voltge for energizing thesolenoid field coil. The lack of signal at a monostable solenoid willcause it to retract [HS switching the valve to the other position andreverslg the flow of the pressurized fluid to the cylinder conolledthereby, whereby to cause the piston ram to return I its other position.

FIG. 5 also illustrates the use of pulse or signal actubed switches orsolenoids to effect such actions of amping, cutting, filling, and thelike. The line 209 :fers to a circuit including a feed-backpotentiometer 09 similar to 208 which operates oil the shaft of mantel16. Potentiometer 209 provides a voltage indicave of the position of themandrel 16 in the extrusion ramber or die, said potentiometer 209 beingconnected I a comparator in 2015b for providing an error signal :1 itsoutput by comparison of said feed-black signal ith the command voltagetnansmitted from amplifier 6 over line 2018b. Said error signal is usedto control Le operation of piston 20. The line 210' functions in similarmanner and connects a feed-back potentiometer ieas uring the stroke orposition of the blade 30 with 1 input to a comparator in 203a. Pulsesignals reprouced by the pick-up head T are anplified and transittedover circuit 211' to momentarily energize a sole- )id for operating themarking or forming tool 21.1 hich advances against the extruding member15 at pre deter-mined intervals in the extrusion cycle and may be usedto externally shape or otherwise toindicate, where specific changes ininternal cross-section occur along the extrusion.

The device referred to by numeral 211 may also comprise any lineallyactuated device for operating on and Withdrawing from the extrudingmember 15. It, 211, may also be a straightening tool, clamp, punch,milling cutter or forming tool which may also be actuated to operate onthe extrusion after the piston 20 has been temporarily stopped as theresult of the generation of the proper command voltage which results inthe movement of the slide block of the variable displacement pump to acenter or neutral position whereby no fluid is delivered to either ofthe ports of cylinder 27.

The notation 21-3 pertains to a sequentially controlled device foroperating on the extrusion 15 Whileit is in motion. The tool 213 maycomprise, for example, such devices as a flying bed press, flying shearor flying saw mounted whereby it may be advanced against the mo uusion,move a brief distance therewith as it extrudes at the speed of extrusionWhile operating thereon after which it retracts and returns to astarting position from which it is thereafter again actuated. The motorsfor powering the member 213 for operating on the work and for advancingit against the Work and moving it at constant speed with the work, maybe controlled by a multicircuit timer 2 12 which is self-resetting andis initially energized by a pulse input thereto generated on input line212' after its reproduction from the tape 200. Said motors may also becontrolled by variable signals recorded on 200 in the manner described.

Also shown in FIG. 5 is a means for effecting control of speed of thepowered roller 29 of FIG. 1 for guiding and driving the extrusion 15, ora segment cut therefrom away from the press 11. A controller 203e,having similar components to those of 203, is provided for controllingthe speed of a motor 29' which drives roller 29 in coacting with one ormore depressor rolls 28 to effect movement of the extrusion. A closedloop speed control system is provided in which the output speed of motor29' is measured by a feed-back tachometer Z9T driven by the shaft of 29which follows the speed command voltage resulting from the amplificationof a signal reproduced by a transducer T from a channel tape 200 whichsignal is of such a nature and that the speed of said drive rolls willvary in proportion to the rate of travel of the extruding member. Themeans for effecting control and variation of the speed of the driverolls comprises the reproduction of a recorded speed command signal by Twhich is utilized for elfecting speed control.

The reference numeral 211a refers to a linear servo such as a solenoidor solenoid actuated ram operated by a signal from a respectivetransducer for urging the cam-lock 48 of FIG. 4 against the stop blade3% to effect its sealing engagement with the die as described. If 211ais a servo such as a monostable solenoid, the presence of a signalreproduced from 200 at its input will cause cam 48 to bear against 30whereas the cessation of generation of said signal will cause 4-8 toretract from 30 o FIG. 6 shows schematically apparatus for control-lingthe hydraulic servo devices heretofore described by means of signalsreproduced from a tape which serve to program a cycle of actions whilecontrolling said servos. An electrical stroker 204' is operated by pulsesignals reproduced from recording tape 200. The electrical stroker 204'includes a command potentiometer 219 and a feed-back potentiometer 218,the resistance elements of which are connected across a power supplyline 225. The wiper arm 2:18 of feed-hack pot 213 is rotated by a shaft213" which is geared to the rotation of the shaft 2&5 of the hydraulicforce strolrer 265 which is driven by the shaft of the electric strokermotor 216. A taohometer 216, coupled to the shaft of motor 216, is usedfor stabilization. The notation 224 refers to a source of referencevoltage across the stator coils of motor 216 and tachometer 216'. Theerror signal or difference between the value of the commandpotentiometer 219 and feed-back potentiometer, is fed to a magneticamplifier 217 which amplifies and applies a control voltage to the coil217' of motor 216. The Wiper 219' of the comm-and potentiometer ispositioned by the shaft 221 of a servo device 220 to give the pot 219 avalue in accordance with the characteristics of the signals recorded onthe tape 200. The servo 220 comprises a pair of ratchet and pawlmechanisms 22-2 and 223 each adapted to elfect rotation of said shaft adegree or unit angle in a respective direction when their respectivesolenoids 222' and 223 are energized. When the monostable solenoid 222'is energized by a pulse reproduced by a transducer T from a firstchannel of the tape 200, the plunger of said [solenoid actuates theratchet pawl mechanism 222 rotating shaft 221 a unit of rotationcounterclockwise thereby rotating wiper arm 219' a unit angle clockwisethrough gears G. When solenoid 223' is energized by a pulse reproducedfrom another channel of 200 by head T the shaft 221 and hence 2-19rotates in the opposite direction.

Control is thus effected by recording groups or trains of pulses alongpredetermined sections of each recording track of 200 and using these toelfect a predetermined movement or pre-positioning of one or more ofsaid hydraulic servos. The length of each pulse train (i.e. the numberof pulses in the train), will determine the degree of movement of theservo. The position of the pulse train, relative to the other recordedsignals, will determine the timing or sequencing of the particularaction, in the extrusion cycle. Control of the speed of movement of theservo may also be effected by the spacing of the pulses in theparticular train. The closer the spacing of pulses, the faster shaft 221will be stepped by the respective solenoid. The electric stroker willthus position the hydraulic stroker more rapidly and the pump willattain its commanded speed more rapidly. Thus, the servo operatedthereby will move to or seek its commanded position more rapidly. Byproviding a pulse train in which each pulse is spaced from the next atan increasing or decreasing distance in the direction they arereproduced from 200, the rate of change of velocity or acceleration ofthe tool may be varied. Thus, depending on the response of the motor ofthe electric stroker in nulling the error signal, any predeterminedposition, speed, velocity or acceleration of the servo and tool may beattained by controlling the number, position and spacing of the pulsesrecorded on the magnetic recording member 200. It is noted that apunched tape and conventional finger limit switch or photocell readingmeans may also be employed in place of the magnetic tape or drum 200.

Also, as the pump 206 may also be utilized to control the action of arotary hydraulic servo or fluid motor, such servos may be used andcontrolled by the pulse system described, to operate and control devicesfor operating on the extruding member. Control of the speed or number ofrotations of the drive rolls 28 and 29 may also be elfected with thedescribed control arrangement, for urging the extrusion out of theextruder. The feed-back tachometer 29T is provided in FIG. 5 for speedcontrol means, if such control is necessary.

FIG. 6a shows means for effecting speed control of such servos as theram cylinder 27 or the motor 29' powering the drive roller 29 whichcoacts with 28 to urge the extrusion 15 from the extruder. Anoutput-speed feed-back tachometer 29T is shown connected in series withthe Wiper arm 219' of a command potentiometer 219", which may becontrolled in the same manner as the wiper of FIG. 6. Tachometer 2.9T isalso connected to the magnetic amplifier 217 and is in parallel circuit10 with the coil 217" of the stroker feed-back tachometer 216. The innerposition loop of the electric stroker is left out to obtain anintegration from the stroker. The pulse or signal controlled shaft 221controls the Wiper 219 or 219" as described to provide a variable speedcommand voltage in accordance with a signal or signals recorded on thetape 200. It is noted that the control means of FIG. 6 may also be usedto provide a form of speed control, since the rate of change of positionof the shaft 205 and hence the rate of variation of the output of thepump 205 which is directly related to the speed of the servo driventhereby, is a function of the rate at which the potentiometer 219 isvaried, which variation depends on the number and spacing or rate ofreproduction of the command pulses used for varying the position ofwiper arm 219. If an analog or variable amplitude signal recorded on achannel of the tape 200 is used as a source of variable command voltageby utilizing a linear reproduction amplifier A the output of saidamplifier may be connected as illustrated in FIG. 6a whereby the rate ofchange of amplitude of the recorded analog signal will produce avariable voltage for controlling the electric stroker motor resulting ina corresponding acceleration. In other words, the acceleration of thecontrolled servo will be a function of the rate of change of thereproduced signals amplitude. Thus, a predetermined variation in outputspeed and acceleration may be provided to occur at a predetermined timeduring the extrusion cycle for elfecting predetermined volume fiow,drive and/ or movement of one or more of the illustrated servos or stopextrusion means.

FIG. 6b is a schematic diagram showing details of the analog signalcontrol means referred to in FIG. 5 for controlling the output of thevariable displacement pump 266 which controls the motion of thehydraulic servo 27. This arrangement may also be used for controllingthe other servos of the extrusion apparatus such as those driving thetools, mandrel, conveying means, etc., which require positional as wellas speed control. The reproduction head T reproduces the analog signalrecorded on its track. Said signal is amplified in the linear amplifierA and provided on its output as a predetermined command voltageproportional to the amplitude of the recorded signal. This commandvoltage is compared with the output voltage of the feed-backpotentiometer 218 which is connected as in FIG. 6 by the gearing to theshaft of the electrical stroker motor. The error signal voltage isamplified in the magnetic amplifier 217 and drives the stroker motoruntil the value of 218 and the output of A are equal. In FIG. 6b and inthe other drawings where provided, the notation P.S. refers to a powersupply.

In the foregoing, I have described my invention only in connection withpreferred embodiments thereof. Many variations and modifications of theprinciples of my invention Within the scope of the description hereinare obvious. Accordingly, I prefer to be bound not by the specificdisclosure herein, but only by the appending claims.

I claim:

1. In an automatic control system the combination of a positional deviceoperated by a hydraulic servo, control means for said hydraulic servoadapted to control the movement of said positional device includingcontrol of the speed and predetermining of the position thereof inrelation to the operation of further servo means to effect asynchronized operation thereof, said hydraulic servo being operativelyconnected to a variable displacement hydraulic pump, the displacement ofsaid pump being variable by a hydraulic stroker operated by an electricstroker coupled to the valve plunger thereof thru precision gearing andhaving a feedback signal generating means for stabilization, closed loopfeedback means in addition to said feedback signal generating means forindicating by an electrical signal the position of said positionaldevice, a source of a variable command voltage which varies in apredetermined manner in relation to further command signals forcontrolling said further servo means, said source of variable commandvoltage being provided by recording an analog signal on a first track ofa recording medium adapted to be driven at a constant speed past meansfor reproducing said signal, a linear amplifier in the output of saidanalog signal reproduction means adapted to amplify and provide a voltage signal over an output circuit which is a function of the signalrecorded on said recording medium, the output of said linear amplifierbeing connected to an input of a comparator adapted also to receive saidposition indicating feedback electrical signal and to provide an errorsignal, which is the difference between said two signals, over an outputcircuit for controlling said electric stroker, said comparator being asumming amplifier, the input to said electric stroker from said summingamplifier including means for amplifying said error signal andcontrolling a motor thereby, said electric stroker having a shaft outputfor driving said hydraulic stroker until the voltage of said feedbackmeans equals the command voltage produced by reproduction of said signalrecorded on said recording medium, said electric stroker therebychanging the position of said hydraulic stroker and varying the deliveryof said pump in proportion to the variation in said recorded signalwhereby the speed of movement and the position of said positional devicemay be controlled and varied in a predetermined manner to effect apredetermined action.

2. Extrusion apparatus comprising in combination, an extrusion diehaving an opening therethru communieating with an extrusion chamber ofan extrusion machine, a minimal area portion of said opening defining anextrusion throat in said die, an automatically controlled servo operatedmeans for varying the area of the throat of said opening, said throatdefining an area in which a material extruded thru said opening isnormally formed to shape which shape it normally retains thereafter, aplurality of prime movers for moving an extrusion material through saidapparatus, said prime movers being operative to vary in the speed oftheir operation by respective electrically controlled servo means, avariable programming means operatively connected to controls for each ofsaid servo means, said programming means including means for generatinga plurality of control signals each during a predetermined time in anextrusion cycle and each adapted to control respective of said servomeans to effect a predetermined variation in the area of the throat ofsaid die opening and corresponding change in the speed of operation ofat least one of said prime movers of said material whereby the velocityof the material controlled by said prime mover varies in proportion tothe change in area of said throat.

3. Extrusion apparatus comprising in combination, an extrusion diehaving an opening therethrough communieating with an extrusion chamberof an extrusion machine, a minimal area portion of said opening definingan extrusion throat in said die, an electrically controlled servooperated means for varying the area of the throat of said opening, saidthroat defining an area in which a material extruded thru said openingis normally formed to shape which shape it may normally retainthereafter, a plurality of prime movers driven by respective servo meansfor moving an extrusion material through said apparatus, said primemovers including a means for delivering an extrusion material to saidextrusion die under suflicient pressufe and mass flow to cause it to beextruded through said die in a cross sectional shape equivalent to thearea of said throat, a second material moving means situated beyond saiddie for engaging the material shaped in said die and conveying it awayfrom said die, said prime movers being operative to vary in the speed oftheir operation by respective electrically controlled servo means, avariable programming means operatively connected to controls for each ofsaid servo means, said programming means including means for generatinga plurality of control signals each during a predetermined time in theextrusion cycle and each adapted to control respective of said servomeans to effect a predetermined variation in the area in the throat ofsaid die opening and predetermined changes in the operation of saidprime movers for said material whereby the extruded shape varies in apredetermined manner with its length and the flow of material into andout of said die is continuous and varies proportionately.

4. Extrusion apparatus in accordance with claim 3, said programmingmeans including means for infinitely varying the speed of both saidprime movers for said material Within a given range and infinitelyvarying the operation of the servo for varying the area of the throat ofthe die opening whereby the velocity of flow of material entering andleaving said die may be regulated in accordance with the change in areaof said throat to maintain the material completely filling the extrusionarea of the throat.

5. Extrusion apparatus in accordance vith claim 3, said programmingmeans comprising a magnetic recording means with means for driving saidrecording means past a plurality of reproduction transducers forreproducing signals recorded on respective channels thereof, the outputof each of said transducers being operatively connected to a control fora respective of said servos for control thereof, said programming meansadapted to effect the generation of signals on each of said transduceroutputs in predetermined time relation to the generation of signals onthe outputs of the others to synchronize the operation of said servosand to define an extrusion cycle for extruding a shape of predeterminedvarying cross section.

6. Extrusion apparatus in accordance with claim 5 including a comparatormeans operatively connected to one of said transducers, the channel ofsaid magnetic recording means from which the comparator means coupledtransducer reproduces having an analog signal recorded thereon along apredetermined length of said magnetic recording means, said comparatormeans adapted for controlling at least one of said servos by utilizingthe reproduced analog signal, said comparator having a signal input froma transducer which provides a feedback signal with the movement of theservo, said comparator including means for using said feedback signaland the signal reproduced from said magnetic recording means to attain apredetermined null condition in the operation of the apparatuscontrolled by the servo.

7. Extrusion apparatus in accordance with claim 6, at least one of theservos being operatively connected to a stop-extrusion tool which isadapted to be infinitely adjustable in position Within a given rangeacross the throat of said die, said feedback signal being derived from atransducer the output of which varies with the position of said stopextrusion tool whereby the position of said tool and variations in itsrate of travel may be controlled and varied in a predetermined manner toprovide infinite variations in the shape of the extrusion defined inpart by the movement of said tool.

8. Extrusion apparatus in accordance with claim 7, said stop extrusiontool comprising a blade mounted on said apparatus, said blade beingmovable across the throat of said die in sealing engagement with theface of the die opening, whereby the cross sectional area of the throatis changed and is defined at least in part by the edge of the bladeprojecting across the throat.

9. Extrusion apparatus in accordance with cla'nn 7, said stop extrusiontool comprising a mandrel which varies in cross section along itslength, said mandrel being axially movable thru the throat of said dieopening a degree to vary the volume exterior of said mandrel and thewall of the throat may be varied to effect a change 13 in thecrosssection of the extrusion and an infinite number of extruded shapes maybe produced.

10. Extrusion apparatus in accordance with claim 2, said apparatusincluding a further electrically controlled servo-operated tool locatedbeyond said extrusion die adjacent material extruding therefrom'forperforming a further operation on the finished extrusion, a control forsaid further servo-operated tool servo which is operatively connected tosaid variable programming means and is adapted to be energized therebyduring a predetermined time in the extrusion cycle to engage and performan operation on a predetermined section of the extrusion.

l1. Extrusion apparatus in accordance with claim 9 said mandrel beingretractable from the throat of said die opening a degree whereby anextrusion may be formed therein and being movable into said throat topermit the formation of a hollow tubular shape, said programming meansincluding means for operating the servo of the material prime movingmeans to increase the flow of material to said die during the retractionof the mandrel whereby a solid portion of an extrusion is produced, andmeans for operating the material prime moving servo to reduce the flowof material to said die when the mandrel is advanced and a hollowtubular extrusion is being produced.

12, Extrusion apparatus in accordance with claim 11 said mandrel havingan opening therein, a servo operated means for feeding a second materialthru said opening, said programming means including means for effectingthe formation of an extrusion consisting of a plurality of solidportions with tubular portions extending for predetermined lengths ofthe extrusion between solid portions, said programming means alsoincluding means for controlling said servo feeding said second materialto deliver a predetermined quantity of a fluid into the volumes definedby the tubular portions of the extrusion before the formation of thesolid portion closing said volume.

13. In an automatic extrusion apparatus as described, a system forcontrolling the operation of said apparatus comprising in combination,an extrusion tool which is movable to vary the cross section of thethroat of an extrusion die to change the cross-sectional shape of amaterial expressing therefrom, said tool being operable by a hydraulicservo for controlling the speed and position of said tool in relation tothe operation of an extrusion material prime moving means which isoperated by a further servo whereby the two servos are sy'nchronized intheir operation, said hydraulic servo being operatively connected to avariable displacement hydraulic pump which is operated by a hydraulicstoker, said hydraulic stroker being operated by an electric strokerwhich has a feedback signal generating means for stabilization, afurther feedback signal generating means for indicating the position ofsaid tool, a source of variable command voltage which varies in apredetermined manner in relation to further control signals generatedfor controlling the operation of said material prime moving servo, saidsource of variable command voltage provided by reproducing an analogsignal from a first channel of a magnetic recording medium which isdriven at constnt speed past reproduction transducing means, a linearamplifier in the output of the reproducing means for said analog signal,adapted to amplify and provide on its output circuit a voltage signalwhich is a function of the signal recorded on said magnetic recordingmedium, the output of said linear amplifier being connected to the inputof a comparator Which is adapted to also receive the signal generated bysaid further feedback position indicating signal generating means, saidcomparator adapted to provide an error signal which is the differencebetween said two signals, means for controlling a servo operating saidelectric stoker with said error signal until the voltage generated bythe tool position indicating signal generating means equals the voltagederived from reproducing said recorded analog signal, said electricstroker thereby changing the position of said hydraulic stroker andvarying the delivery of said hydraulic pump in proportion to thevariation in the recorded analog signal whereby the speed of movementand the position of said tool is controlled in a predetermined mannerand varied to provide an extrusion of a predetermined shape which varieswith length.

14. In an automatic control system the combination of a positionaldevice operated by a hydraulic servo, control means for said hydraulicservo adapted to operate said servo in a manner to control the speed ofmovement and position of said positional device in synchronized relationto the operation of a further servo driven device, said hydraulic servobeing operatively connected to a variable displacement hydraulic pumpthe displacement of said pump being variable by a hydraulic strokerwhich is operated by an electric stroker having a feedback signalgenerating means for stabilization, a further feedback signal generatingmeans adapted for indicating by an electrical signal the position ofsaid positional device, means for generating a first command signalwhich varies in a predetermined manner in relation to further signalsfor controlling said further servo driven device, said first commandsignal generating means comprising in combination with a magneticrecording medium, a means for driving said magnetic recording medium atconstant speed past a transducing means for the repetitive playback of avariable control signal recorded thereon, the reproduction of saidvariable control signal from said magnetic recording medium beingtransmitted to a linear amplifier the output of which is operativelyconnected to a comparator which is also adapted to receive signals fromsaid further feedback signal generating means and to provide on itsoutput an error signal which is the difference between the two receivedsignals, means for amplifying said error signal and using it to controlthe servo operating said electric stroker which in turn drives saidhydraulic stroker until the error signal disappears, said electricstroker thereby changing the position of said hydraulic stroker andvarying the delivery of said pump in proportion to the variation in therecorded signal whereby the speed of movement and position of thepositional device may be controlled and varied in a predetermined mannerto effect a predetermined action.

15. Extrusion apparatus comprising an extrusion machine having anextrusion chamber, a die having an opening therethrough communicatingwith said chamber, said opening having a minimal area portion definingan extrusion throat of said die, an automatically controlled servooperated means for varying the area of said throat, said throat definingan area in which material extruded through said opening is normallyformed to shape with this shape normally being retained thereafter,prime moving means for moving an extrusion material through saidapparatus, controls for said servo operated means, programming meansconnected to operate said controls, said programming means includingmeans for generating a programmed sequence during a predetermined timein an extrusion cycle and adapted to control operation of said servooperated means to effect a predetermined variation in the area of thethroat coordinated with speed of the prime moving means whereby theshape of the extrusion is varied along its length in a predeterminedmanner.

16. The apparatus set forth in claim 15 also comprising controlled servomeans operatively connected to control the speed of the prime movingmeans, controls for the controlled servo means, programming meansconnected to operate said last recited controls, said last recitedprogramming means including means for generating a programmed sequencecoordinated with the previously recited programmed sequence, wherebyoperation of the prime moving means varies in a predetermined mannerproportional to the change in area of the extrusion throat.

17. An automatically controlled apparatus for produc ing an extrusion ofpredetermined cross-section during a controlled extrusion cyclecomprising in combination an extrusion chamber for containing extrusionmaterial, an extrusion die defining a portion of the wall of saidchamber and including an opening in which the extrasion material isformed to shape during extrusion, variable means for controlling thesize and shape of the extrusion opening, a prime moving means for movingsaid material to said die and through said opening, a first oontrollerfor operating said variable means according to a predetermined program,a second controller for varying the operating speed of said prime movingmeans, and means coordinating operation of said controllers to producean extrusion whose shape varies along its length in a predeterminedmanner.

18. An automatically controlled apparatus for producing an extrusionduring a program controlled extrusion cycle comprising in combination anextrusion chamber for containing extrusion material, an extrusion diedefining a portion of the wall of said chamber and including an openingin which the extrusion material is formed to shape daring extrusion, aprime moving means for moving the extrusion material to said die andthrough said opening, servo means (operatively connected to said primemoving means a controller means operatively connected to said servomeans for controlling the rate of operation of said prime moving meansthereby pre determining the rate of movement of said extrusion materialthrough said chamber, variable controls for said controller means,programming means connected to opertae said variable controls, saidprogramming means including means for generating a predeterminedprogrammed sequence defining an extrusion cycle extending over apredetermined time interval, means presenting said program to saidvariable controls in a predetermined order for sequentially controllingthe operation of said during a subsequent time interval.

References Cited in the file of this' patent or the original patentUNITED STATES PATENTS 1,063,071 Schlcuning May 27, 1913 1,411,170 KahrMar. 28, 1922 1,482,015 Kielbcrg Jan. 29, 1924 1,974,618 Lent Sept. 25,1934 2,015,681 Kesty Oct. 1, 1935 2,044,961 Wancr June 23, 19362,063,013 Cooper Dec. 8, 1936 2,366,417 lviacMillin Ian. 2, 19452,411,971 MacMiIlin et a1 Dec. 3, 1946 2,435,643 Bean Feb. 10, 19482,485,523 Ashbaugh Oct. 18, 1949 2,497,724 Gilson et a1 Feb. 14, 1950 12,580,787 Johnson Ian. 1, 1952 2,615,203 Dupree Oct. 28, 1952 2,615,658Young Oct. 28, 1952 2,632,202 Haines Mar. 24, 1953 2,683,899 ReichenbachJuly 20, 1954 2,747,222 Koch et a1. May 29, 1956 2,747,224 Koch et a1.May 29, 1956 2,750,625 Colombo June 19, 1956 2,778,493 Kreidler Jan. 22,1957 2,780,835 Sherman Feb. 12, 1957 2,834,983 Morton May 20, 19582,903,130 Reichl Sept. 8, 1959 2,916,792 Crook et a1 Dec. 15, 19592,919,467 Mercer Jan. 5, 1960

